Tensile member with tension indicator

ABSTRACT

A tensile member adapted to indicate the tension on it has a pin reciprocable in a bore in the tensile member the bottom of which constitutes a stop for the pin. A disc spring is coupled to the pin. The disc spring is urged into contact with a surface of the tensile member surrounding the entrance to the bore when the pin is pressed into the bore. The disc spring becomes distorted and snaps through when the distance between the bottom of the bore and the entrance of the bore increases by a given amount as a result of elongation of the tensile member caused by tensioning it.

United States Patent 1 1111 3,776,031

Tngg Dee/4, 1973 [54] TENSILE MEMBER WITH TENSION 2,434,984 1/1943Bolesky et al. 73/373.3 x INDICATOR 1 2,850,937 9/1958 Ralston 85/623,539,234 6/1971 Trigg 85/62 Inventor: 4 J Victor g gg, Odiham,3,243,923 5/1966 131a1 616 73/33 F England 3,561,260 2/1971 Reynolds....73/33 F 2,995,033 8/1961 Stifano 73/33 F [73] Assignee: InternationalEngineering Concusionaries Limited,

waltomonqhames Surrey, Primary Examiner-Richard C. Q ueisser England 1Assistant Examiner-Arthur E. Karkosz AttorneyWoodhams, Blanchard & Flynn[22] Filed: Aug. 16, 1971 [21] A p]. N01: 172,019 57 AB RA T v I Atensile member adapted to indicate the tension on. it 7 ForeignApplication Priority Data has a pin reciprocable in a bore in thetensile member Aug. 19, 1970 Great Britain 39,995 the bottom of whichconstitutes a p for the P h disc spring is coupled to the pin. The discspring is 52 US. Cl. 73 95, /62 utgedinto Contact with a Surface of thetensile [51] Int, Cl. G01n 3/08 her Surrounding the entrance to theborewhen the P 53 Field of Search 73/88 F, 85/62, is Ptessed into the bote-The disc Spring becomes 35 1 32 T 1 T torted and snaps through when thedistance between the bottom of the bore and the entrance of the bore 5 IReta-"Ices Cited increases by a given amount as a result of elongationUNITED, STATES PATENTS of the tensile member caused by tensioning it.1,767,709 6/1930 Smith 713/3783 I 8 Claims, 5 Drawing Figures .4 D b 16Z 5 5 1 TENSILE -MEMBER WITH TENSION INDICATOR The present inventionrelates to a tensile member provided with a tension indicator andprovides a tensile member having a member moveable relative thereto andtowards a stop for the moveable member fixedrelative to a region of thetensile member, and a bi-stable resilient member arranged to be urged bythe moveable member to bear against a surface of the tensile memberremote from the said region when the moveable member is urged towardsthe stop, whereby the resilient member becomes distorted, and therebysnaps through from one stable configuration to anotherwhen the distancebetween the said region and the said surface increases by a given amountas a result of elongation of the tensile member caused by tensioningthereof.

With this arrangement, the resilient member and moveable member can beso set that when the desired tension is reached, the moveable member canbe displaced relative to the said surface sufficiently to distort theresilient member as it bears against the said surface to apoint at whichit snaps through. In use, pressure can be applied to urge the moveablemember towards the stop and the tensile member can be progressivelytensioned. An audible click as the resilient member snaps throughindicates that the desired tensioning has been reached.

Advantageously, means are provided for resiliently resisting movement ofthe moveable member towards the stop, and a shoulder is provided on thetensile member spaced from and facing towards the said surface, thmoveable member, when movingaway from the stop, pressing the resilientmember against the shoulder, whereby when the resilient member hassnapped through it will snap back to its original resilience andconfiguration when pressure on the moveable member is relaxed. Thisarrangement maintains the resilient member normally in its originalresilience and configuration, whereby testing of the tensile member inuse, by pressing the moveable member towards the stop, is facilitated,and permits use of the tensile member under water. The tactile sensationas the resilient member reached.

Usually, the resilient member is kept spaced from the said surface onthe tensile member, except when testing or setting is taking place.

The present invention will now be more fully described with the aid ofexamples illustrated in the accompanying drawings in which:

FIG. 1 shows in section a tensile member in accordance with theinvention together with a tool for testing the tensile member;

FIG. 2 shows in section a portion of the tensile member of FIG. 1 beforesetting;

FIGS. 3 and 4 show in section further forms of tensile members inaccordance with the invention; and

FIG. 5 shows in section a portion of the upper end of the tensile memberof FIG. 3 of 4 in the course of assembly.

same reference numberals. Referring to the drawings a tensile member 1has a bore 2 therein and a pin 3 which is a sliding fit in the bore. Thebottom of the bore 2 constitutes a stop limiting movement of the pin 3in the bore. When the pin 3 is displaced towards the bottom of the bore2 a bistable disc spring 4, of the sort known as a Belleville washer, isurged by the pin against a surface 6 on the tensile member 1 and is thusdistorted. The disc spring 4 may be in the formof a plain disc or mayhave radially extending slots extending either outwardly from thecentral aperture orinwardly from the circumference. The spring 4 iscarried on the pin 3 between op-' posing shoulders formed by acircumferential groove 7, and is normally spaced from the surface 6.When the tensile member 1 is un-stressed,the stop constituted by thebottom of the bore 2prevents the pin 3 from being displaced sufficientlytodistort the disc spring 4 to the point at which the disc spring cansnap through. However, when tension is applied to the tensile member 1,the member elongates and the distance between the bottom of the bore2and the surface 6 increases, permitting the pin 3 to be displacedfurther into the bore. The disc spring 4 and pin 3 are so set that whenthe desired tension is reached the displacement of the pin 3 thenpossible is sufiicient to distort the spring 4 to a point at which thespring snapsthrough, to the configuration shown in broken lines inFIG. 1. When the spring 4 snaps through it gives an audible click,providing an indication that the desired tension has been reached.

In the examples shown in the drawings a compression spring 8 in thebottom of the bore 2 resiliently resists movement of the pin towards thebottom of the bore,

and returns the pin 3 when pressure onthe pin is re laxed. A flexiblebutton 9, conveniently of plastics or metal, and which is a force fit inan aperture in the ten sile member has an annular shoulder on thesurface facing towards the surface 6, against which the pin 3, whenreturned by the action of the spring 8, presses the disc 'spring 4,whereby the disc spring snaps through to its original resilience andconfiguration.

In manufacture of the tensile member shown in FIG. 1, the pin 3 isinitially provided with a cylindrical end portion shown at 12 in FIG. 2.The end portion 12 is made relatively soft compared with the remainderof the pin, for example by conventional heat treatment, so as to beplastically deformable. With all the components illustrated assembled inthe positions shown in the drawings, the tensile member is loaded to apredetermined tension corresponding to the load which it is desired tomaintain in use, and pressure greater than that which can be exerteddirectly by hand is applied gradually to the pin 3, to cause plasticdeformation of the plastically deformable end portion 12 into theconfiguration shown in FIGS. 1 and 3 thus permitting displacement of thepin towards the bottom of the bore 2, until the disc spring4 just snapsthrough, and the pressure on the pin is then relaxed.

The use in setting of pressure greater than that which can be exerted byhand ensures that the softened end portion 12 of the pin 3 will not bedeformed accidentally in use of the tensile member when hand pressure isapplied to the pin to test that the desired tension in the tensilemember is maintained.

In the examples shown in FIGS. 3 and 4 the pin 3 that exertable byhandis used to press the pin 3 into the bore with sufficient force todislodge the scroll-pin 22 and push it deeper into the tube 21. In use,when hand pressure is exerted on the pin 3, the scroll-pin 22 cannot bedislodged and its engagement with the bottom of the bore 2 limitsmovement of the pin 3.

As shown in FIG. 5, the disc spring 4 and pin 3 of the tensile member ofFIGS. 3 and 4 can be assembled by initially forming the tube-form pin 3to taper towards its end so that the spring 4 can be easily fed onto theend of the pin 3 until its apertured middle coincides with the groove 7,whereafter the end of the pin 3 is spun outwards to secure the discspring 4 in the groove 7.

In order to improve sensitivity in testing, the testing pressure can beapplied with a spring-loaded pointed tool 13 illustrated in FIG. 1 whichis mounted in a holder 14 with a spring 16 which has a spring ratesimilar to the spring 8, and which will not become solid before the discspring 4 snaps through. A dimple can be provided in the outer surface ofthe button 9 to locate the point of the tool, and the button 9 may belocated on the head of the pin 3 by a projection 17 in FIG. 1 whichengages a transverse slot 18 in the pin 3.

In the forms shown in FIGS. 3 and 4 the button 9 is located on the pin 3bya projection 23 which engages and is a tight fit in the tube 21constituting the upper end of the pin 3. The form of button 9illustrated in FIG. 3, having concentric grooves in its upper surface ispreferred to that of FIG. 4 since it has no undercut portions and isthus easier to produce by conventional plastics-material formingtechniques whilst having sufficient flexibility in use. It iscontemplated that the resilient properties of the button 9 may beemployed instead of the spring 8 for resiliently resisting movement ofthe pin 3.

Although the arrangement shown in the drawings are preferred, otherarrangements can be employed. In one modification, the stop isconstituted by a volute spring press-fitted into the bottom region ofthe bore 2 and bearing on the bottom of the pin 3. In setting, pressuregreater than that exertable directly by hand is used to press the pininto the bore with sufficient force to dislodge the volute spring andpush the volute spring deeper into the bore. In use, when hand pressureis exerted on the pin, the volute spring cannot be dislodgedand forms astop when the coils of the spring engage with one another and the springbecomes solid.

In a further modification, the pin is located in the bottom of the boreby a Mills pin seated in the bottom of the bore and arranged with itspoint facing away from the bottom of the bore and wedging in a hole inthe pin tapering in the direction away from the bottom of the bore. Thehead of the first-mentioned pin constitutes a stop for the button whichis mounted normally spaced from the head of the pin, and the surface ofthe button facing towards the surface 6 bears on the spring 4 whenpressed towards the head of the pin. In setting, pressure greater thanthat exertable by hand is applied to the button to press thefirst-mentioned pin onto the Mills pin and to wedge the Mills pinprogressively deeper in the hole in the pin.

I claim:

1. In combination: a tensile member having a stop fixed relative to afirst region thereof, and means defining a reaction surface on saidtensile member fixed relmeans including a movable member movable by,

hand pressure relative to said tensile member, means defining a shoulderspaced from and facing towards said reaction surface, and a bi-stableresilient member between said reaction surface and said shoulder andoperatively coupled to said movable member, said bi-stable resilientmember being resiliently deformable between first and second stableconfigurations, whereby when said movable member is urged in a firstdirection, said resilient member is urged towards said surface andbecomes distorted and snaps through from said first stable configurationto said second stable configuration when the distance between said firstregion and said reaction surface increases by a given amount as a resultofelongation of said tensile member caused by tensioning thereof; andwhereby said movable member when moving in a second direction oppositeto said first direction presses said resilient member against saidshoulder so that said resilient member snaps through from said secondstable configuration to said first stable configuration. 2. Thecombination according to claim 1, wherein said tensile member has a'bore. therein, said movable member being movably positioned within saidbore, the

bottom of said bore constituting said stop.

3. The combination according to. claim 2, in which the surface of thetensile member adjacent the entrance to said bore constitutes saidreaction surface remote from said first region.

4. The combination according to claim 2, including a button mounted onsaid tensile member and located at the entrance of said bore outwardlyfrom said movable member, said shoulder being provided on said button.

5. The combination according to claim 1, including means resilientlyresisting movement of said movable member towards said stop.

6. The combination according to claim 1, wherein said bi-stableresilient member is a disc spring.

7. The combination according to claim 1, wherein said movable member isslidably supported in said tensile member for relative linear movementtherebetween.

8. An indicator structure comprising: a first member having a reactionsurface; means defining a shoulder spaced from and facing towards saidreaction surface; a movable member movable by hand pressure relative tosaid surface; a bi-stable resilient member between said reaction surfaceand said shoulder and engaging and moving with said movable member, saidbi-stable resilient member being movable between two stable Iconfigurations whereby said movable member can be moved by hand pressureto urge said resilient member towards said reaction surface and snapsaid resilient member through from one stable configuration to anotherstable configuration; and resilient means which urge said movable memberto move said resilient member towards said shoulder when hand pressureis released after said resilient member has snapped through to saidanother stable configuration, said, resilient means being stronger inaction than said resilient member whereby said resilient member candistort against said shoulder and snap back to said one stableconfiguration.

1. In combination: a tensile member having a stop fixed relative to afirst region thereof, and means defining a reaction surface on saidtensile member fixed relative to a second region of said tensile memberremote from said first region; and indicator means for determiningwhether a desired tension exists in said tensile member, said indicatormeans including a movable member movable by hand pressure relative tosaid tensile member, means defining a shoulder spaced from and facingtowards said reaction surface, and a bi-stable resilient member betwEensaid reaction surface and said shoulder and operatively coupled to saidmovable member, said bi-stable resilient member being resilientlydeformable between first and second stable configurations, whereby whensaid movable member is urged in a first direction, said resilient memberis urged towards said surface and becomes distorted and snaps throughfrom said first stable configuration to said second stable configurationwhen the distance between said first region and said reaction surfaceincreases by a given amount as a result of elongation of said tensilemember caused by tensioning thereof; and whereby said movable memberwhen moving in a second direction opposite to said first directionpresses said resilient member against said shoulder so that saidresilient member snaps through from said second stable configuration tosaid first stable configuration.
 2. The combination according to claim1, wherein said tensile member has a bore therein, said movable memberbeing movably positioned within said bore, the bottom of said boreconstituting said stop.
 3. The combination according to claim 2, inwhich the surface of the tensile member adjacent the entrance to saidbore constitutes said reaction surface remote from said first region. 4.The combination according to claim 2, including a button mounted on saidtensile member and located at the entrance of said bore outwardly fromsaid movable member, said shoulder being provided on said button.
 5. Thecombination according to claim 1, including means resiliently resistingmovement of said movable member towards said stop.
 6. The combinationaccording to claim 1, wherein said bi-stable resilient member is a discspring.
 7. The combination according to claim 1, wherein said movablemember is slidably supported in said tensile member for relative linearmovement therebetween.
 8. An indicator structure comprising: a firstmember having a reaction surface; means defining a shoulder spaced fromand facing towards said reaction surface; a movable member movable byhand pressure relative to said surface; a bi-stable resilient memberbetween said reaction surface and said shoulder and engaging and movingwith said movable member, said bi-stable resilient member being movablebetween two stable configurations whereby said movable member can bemoved by hand pressure to urge said resilient member towards saidreaction surface and snap said resilient member through from one stableconfiguration to another stable configuration; and resilient means whichurge said movable member to move said resilient member towards saidshoulder when hand pressure is released after said resilient member hassnapped through to said another stable configuration, said resilientmeans being stronger in action than said resilient member whereby saidresilient member can distort against said shoulder and snap back to saidone stable configuration.